head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, and it is a single point.

Optimization · Pure Optimization
A faction-driven RPG-shooter where build and route planning shape every ending.

Optimization · Pure Optimization
A tower-defense game about placing traps along paths to protect baby monsters.
Fallout: New Vegas leans Optimization (Pure Optimization); PixelJunk Monsters 2 leans Optimization (Pure Optimization).
Fallout: New Vegas leans a little harder on execution, though the gap is small.
Fallout: New Vegas
Shooter inputs with VATS assist
PixelJunk Monsters 2
Some real-time placement timing under wave pressure.
Fallout: New Vegas leans a little harder on reads, though the gap is small.
Fallout: New Vegas
Scripted factions and enemies
PixelJunk Monsters 2
Enemy waves are scripted, not adaptive.
PixelJunk Monsters 2 leans a little harder on variance, though the gap is small.
Fallout: New Vegas
Some loot and crit RNG
PixelJunk Monsters 2
Wave composition adds some unpredictability.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Fallout: New Vegas
Faction routing, perks, builds heavily rewarded
PixelJunk Monsters 2
Tower placement and upgrade paths are deeply solvable.
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.